论文标题
局部Seyfert 2星系中的分子气体特性
The molecular gas properties in local Seyfert 2 galaxies
论文作者
论文摘要
我们介绍了局部Seyfert 2星系样品的分子气体特性的多波长研究，以评估在33个局部Seefert 2 2个星系的样品中，活性银河核（AGN）的存在是否会影响星际培养基（ISM）性质。我们比较了分子气体含量（MH2），该分子气体含量（MH2）衍生自AGN样品的新和档案低J CO系测量和恒星形成星系的对照样品（SFGS）。 AGN和对照样品的表征都以宿主 - 果实特性（例如，分别为MSTAR和MDUST；以及恒星形成速率，SFR）来表征。我们还研究了AGN活性对中红外（MIR）中多环芳烃（PAH）分子的发射的影响，这是波段，其中遮盖的AGN从粉尘中获取的发射最大。 AGN托管在较少的星系中（即，log（mstar/msun）<10.5; log（mdust/msun）<7.5）显示出相对于在恒星和尘埃质量中匹配的SFG的较大的分子气体含量。当比较其耗竭时间（TDEP〜MH2/SFR）时，AGN显示TDEP 〜0.3-1.0 GYR，类似于在SFG的对照样品中观察到的tdep。 Seyfert 2星系显示在MIR中核活性越来越大的优势下表现出轻率的PAH光度。我们没有发现明确的证据表明，塞弗特星系中银河系的分子气体储量有系统地减少相对于SFG。这与最近的研究一致，该研究表明，在亚基大小的区域中，分子气体含量仅降低，其中积分超质量黑洞的发射占主导地位。尽管如此，我们表明AGN活性对ISM的影响清晰可见为PAH光度的抑制。
We present a multi-wavelength study of the molecular gas properties of a sample of local Seyfert 2 galaxies to assess if, and to what extent, the presence of an active galactic nucleus (AGN) can affect the Interstellar Medium (ISM) properties in a sample of 33 local Seyfert 2 galaxies. We compare the molecular gas content (MH2), derived from new and archival low-J CO line measurements of a sample of AGN and a control sample of star-forming galaxies (SFGs). Both the AGN and the control sample are characterised in terms of host-galaxy properties (e.g., stellar and dust masses, Mstar and Mdust, respectively; and star formation rate, SFR). We also investigate the effect of AGN activity onto the emission of polycyclic aromatic hydrocarbon (PAH) molecules in the mid-infrared (MIR), a waveband where the dust-reprocessed emission from the obscured AGN contributes the most. The AGN hosted in less massive galaxies (i.e., log(Mstar/Msun)<10.5; log(Mdust/Msun)<7.5) show larger molecular gas content with respect to SFGs matched in stellar and dust mass. When comparing their depletion time(tdep~MH2/SFR), AGN show tdep~0.3-1.0 Gyr, similar to those observed in the control sample of SFGs. Seyfert 2 galaxies show fainter PAH luminosity at increasingly larger dominance of the nuclear activity in the MIR. We find no clear evidence for a systematic reduction of the molecular gas reservoir at galactic scale in Seyfert galaxies with respect to SFGs. This is in agreement with recent studies showing that molecular gas content only is reduced in regions of sub-kpc size, where the emission from the accreting supermassive black hole dominates. Nonetheless, we show that the impact of AGN activity on the ISM is clearly visible as suppression of the PAH luminosity.
